thats not true. bent pushrods dont unbend when they warm up. but a lifter will pump up after a few seconds of running. the hydraulic spring/valve inide the lifter is what would be damaged in my example. not the rollers.

piston slap is also common and will make noise on first startup then go away after a very short time. your not talking about that are you?

 

It never made this noise before last night.

 

I went home and started it up cold. No noise at all. The car feels perfectly fine throughout the entire RPM range. This is too weird????

 

OK, I think I got this one figured out!!!!! I talked to my boss (ASE Mechanic) and he said that on the 98 F-body, they had a lot of issues with the A/C compressor clutch making noise on start up. I pulled off the A/C belt and it runs extremely quiet. I am just praying it stays that way.